Nokia Maps is a free program with free maps. But (voice) navigation is not free. Actually it's damn expensive.

Unless you are willing to set the clock forward.

Nokia offers a free 3-day trial for its navigation feature. The clock starts running whenever you want, and your phone itself is the clock: if you set the date of your phone to somewhere in the future, e.g. your birthday two years from now, this is when the 3-day trial starts.

So fastforward to 2010 before you start up Nokia Maps, activate the 3-day trial, and go navigate for free. When you're done navigating, set your phone's date back to today. You don't want to miss all those calendar alarms, do you?

Next time you want to navigate, forward your clock to your birthday two years from now before launching Nokia Maps and you'll have another three free days. You can repeat this as often as you like.

This trick only works with Nokia Maps 1. There's no more free trial in Nokia Maps 2.0.

If you don't want to pay data charges for downloading map data over your mobile internet connection, you can preload all maps on your phone with Nokia Map Loader or with this Nokia Map Loader Alternative.

Note: you can set the time bomb only once, so this trick only works if you didn't activate your trial before. If you did, there's still a way out: a new SIM card will give you a clean slate.